Effect of Carbonic Anhydrase on CO2 Separation Performance of Thin Poly(amidoamine) Dendrimer/Poly(ethylene glycol) Hybrid Membranes

Abstract

The effect of carbonic anhydrase (CA) on the separation performance of thin poly(amidoamine) (PAMAM) dendrimer/poly(ethylene glycol) (PEG) hybrid membranes was investigated. CA, a type of enzyme, was used to promote CO2 hydration and dehydration reactions and to assess whether these reactions were the rate-limiting step in CO2 permeation through the membrane. The relationship between the membrane thickness and the CO2 permeance was evaluated in CO2/H2 or CO2/He separation using PAMAM/PEG hybrid membranes (thickness: 10–100 μm) with and without CA. Without CA, the CO2 permeance of PAMAM/PEG hybrid membranes was not inversely proportional to the membrane thickness. On the other hand, with CA, the CO2 permeance was inversely proportional to the membrane thickness. It was implied that, without CA, the rate-limiting step of CO2 transport was either the CO2 hydration reaction at the feed side or the CO2 dehydration reaction at the permeate side. On the other hand, with CA addition, the rate-limiting step of CO2 transport was diffusion, and CO2 permeance could be increased without sacrificing the selectivity by reducing membrane thickness. The effect of the position of CA (i.e., on the surface and/or reverse surface) on CO2 separation performance was investigated to evaluate which reaction was the rate-limiting step of CO2 permeation through the membrane. It was suggested that the rate-limiting step of CO2 permeation was CO2 dehydration reaction at the permeate side.

CO2‐facilitated transport membranes prepared by blending polyvinyl alcohol and various water‐absorbing agents

“…The target system in the present study was CO 2 /H 2 produced from the water‐gas shift reaction. To ensure safety, He was used instead of H 2 as in the past experiments 25,26 . The relationship between the permeances of He and H 2 is as follows: Q He ≈ 0.8 Q H₂ .…”

“…The relationship between the permeances of He and H 2 is as follows: Q He ≈ 0.8 Q H₂ . The permeance of CO 2 ; however, was almost the same for both CO 2 /He and CO 2 /H 2 separation 26 . The prepared membrane was first set in a cell for evaluation, and in the heating furnace, the cell and a stainless pipe were connected.…”

“…In the last few years, such polymer membranes have been extensively developed 2,4,10,12–20 . Polymer membranes containing an amine‐based dendrimer have been developed for efficient CO 2 separation 11,21–26 . In addition, polymer membranes containing a CO 2 carrier have been developed 14,15,27–33 .…”

Development of a polyvinyl alcohol/sodium polyacrylate composite polymer membrane with cesium carbonate as a mobile carrier for high‐performance CO2 capture

“…Previous studies have confirmed that the separation performance is improved when either carbonate or amine‐based additives are included in the membrane 12,25–34 . Carbonate and amine moieties, which function as CO 2 carriers, require water to enhance their chemical reaction with CO 2 25,35,36 .…”

“…[20][21][22][23][24] Previous studies have confirmed that the separation performance is improved when either carbonate or amine-based additives are included in the membrane. 12,[25][26][27][28][29][30][31][32][33][34] Carbonate and amine moieties, which function as CO 2 carriers, require water to enhance their chemical reaction with CO 2 . 25,35,36 Among the alkyl carbonates, cesium carbonate is most frequently used as an additive for the CO 2 separation membrane.…”